Students in a Course-Based Undergraduate Research Experience Course Discovered Dramatic Changes in the Bacterial Community Composition Between Summer and Winter Lake Samples.

Course-based undergraduate research experience (CURE) courses incorporate high-impact pedagogies that have been shown to increase undergraduate retention among underrepresented minorities and women. As part of the Building Infrastructure Leading to Diversity program at the University of Detroit Mercy, a CURE metagenomics course was established in the winter of 2019. Students investigated the bacterial community composition in a eutrophic cove in Lake Saint Clair (Harrison Township, MI, United States) from water samples taken in the summer and winter. The students created 16S rRNA libraries that were sequenced using next-generation sequencing technology. They used a public web-based supercomputing resource to process their raw sequencing data and web-based tools to perform advanced statistical analysis. The students discovered that the most common operational taxonomic unit, representing 31% of the prokaryotic sequences in both summer and winter samples, corresponded to an organism that belongs to a previously unidentified phylum. This result showed the students the power of metagenomics because the approach was able to detect unclassified organisms. Principal Coordinates Analysis of Bray-Curtis dissimilarity index data showed that the winter community was distinct from the summer community [Analysis of Similarities (ANOSIM) r = 0.59829, n = 18, and p < 0.001]. Dendrograms based on hierarchically clustered Pearson correlation coefficients of phyla were divided into a winter clade and a summer clade. The conclusion is that the winter bacterial population was fundamentally different from the summer population, even though the samples were taken from the same locations in a protected cove. Because of the small class sizes, qualitative as well as statistical methods were used to evaluate the course's impact on student attitudes. Results from the Laboratory Course Assessment Survey showed that most of the respondents felt they were contributing to scientific knowledge and the course fostered student collaboration. The majority of respondents agreed or strongly agreed that the course incorporated iteration aspects of scientific investigations, such as repeating procedures to fix problems. In summary, the metagenomics CURE course was able to add to scientific knowledge and allowed students to participate in authentic research.

An epifluorescent attachment improves whole-plant digital photography of Arabidopsis thaliana expressing red-shifted green fluorescent protein.

BACKGROUND AND AIMS: Studies have shown that levels of green fluorescent protein (GFP) leaf surface fluorescence are directly proportional to GFP soluble protein concentration in transgenic plants. However, instruments that measure GFP surface fluorescence are expensive. The goal of this investigation was to develop techniques with consumer digital cameras to analyse GFP surface fluorescence in transgenic plants. METHODOLOGY: Inexpensive filter cubes containing machine vision dichroic filters and illuminated with blue light-emitting diodes (LED) were designed to attach to digital single-lens reflex (SLR) camera macro lenses. The apparatus was tested on purified enhanced GFP, and on wild-type and GFP-expressing arabidopsis grown autotrophically and heterotrophically. PRINCIPAL FINDINGS: Spectrum analysis showed that the apparatus illuminates specimens with wavelengths between ∼450 and ∼500 nm, and detects fluorescence between ∼510 and ∼595 nm. Epifluorescent photographs taken with SLR digital cameras were able to detect red-shifted GFP fluorescence in Arabidopsis thaliana leaves and cotyledons of pot-grown plants, as well as roots, hypocotyls and cotyledons of etiolated and light-grown plants grown heterotrophically. Green fluorescent protein fluorescence was detected primarily in the green channel of the raw image files. Studies with purified GFP produced linear responses to both protein surface density and exposure time (H(0): ß (slope) = 0 mean counts per pixel (ng s mm(-2))(-1), r(2) > 0.994, n = 31, P < 1.75 × 10(-29)). CONCLUSIONS: Epifluorescent digital photographs taken with complementary metal-oxide-semiconductor and charge-coupled device SLR cameras can be used to analyse red-shifted GFP surface fluorescence using visible blue light. This detection device can be constructed with inexpensive commercially available materials, thus increasing the accessibility of whole-organism GFP expression analysis to research laboratories and teaching institutions with small budgets.